The main factors affecting catalog performance are the amount of I/O required for the catalog and the subsequent amount of time it takes to perform the I/O. These factors can be reduced by caching catalogs in special caches used only by catalogs.

If the master catalog only contains entries for catalogs, catalog aliases, and system data sets, the entire master catalog is read into main storage during system initialization. Because the master catalog, if properly used, is rarely updated, the performance of the master catalog is not appreciably affected by I/O requirements.

Performance can also be enhanced by specifying certain options when defining a catalog. These performance attributes are discussed in Choosing Options to Adjust Catalog Performance, and Setting the Catalog Control Interval and Area Size.

Sharing a catalog between systems also affects performance. See The Effect of Sharing Catalogs on Cache Usage.

In summary, catalog performance is mainly enhanced by caching the catalog. If a catalog is cached, the reduced I/O to the catalog reduces the effect of other factors on catalog performance. Otherwise, considerations affecting catalog recovery should take precedence over performance considerations.